1. Technical Field
The present invention is directed to an improvement to writing instruments, wherein the writing instrument is easily and inexpensively capable of accepting ink cartridges of longer or shorter than normal length. In particular, the improvement includes a resilient spacing element which decreases the nominal length of the cartridge chamber, but allows compressible contact with a cartridge longer than that nominal length.
2. Discussion of the Related Art
Ink writing instruments are well known in the art and are available in both disposable and non-disposable forms. Non-disposable forms typically utilize replaceable ink cartridges that are inserted into a chamber within the instrument. When one replaceable ink cartridge is exhausted, a user simply removes it and inserts a new one.
Not all cartridges fit all writing instruments however; non-disposable writing instruments that employ ink cartridges are typically constructed with the intention of using cartridges of a specified length. Therefore, a user is often forced to rely upon one brand or type of cartridge for a particular writing instrument. Complicating this situation are cartridges that are close to normal size but are somewhat shorter or longer. Shorter cartridges may fit within a prior art writing instrument, but because they are of less than normal length, remain loose within the cartridge chamber. Although the user may be able to make use of the writing instrument with such a cartridge installed, the cartridge tends to slip and slide around within the chamber, resulting in noise and an unstable feeling within the user's hand, thus distracting the user from making smooth strokes.
Similarly annoying are ink cartridges that are of slightly longer than normal length. When a cartridge is substantially longer than normal, the user can tell at a glance that it will not fit within the chosen writing instrument. However, with cartridges that are only slightly longer than normal, the user cannot discern whether it will fit or not until he or she attempts to install it within the cartridge chamber.
Most non-disposable writing instruments consist of two or more separable sections which, when joined, create the cartridge chamber and envelope the ink cartridge. When the sections of a particular writing instrument connect and release via screwing and unscrewing complementary threaded portions, the writing instrument may, by not completely screwing the portions together, be capable of enclosing a cartridge that is too long. This remains unsatisfactory to the user, however, as the instrument then has a tendency to unscrew further, to the point of disassembly. In addition, the incomplete union of the instrument segments is likely to feel uncomfortable within the user's grasp.